Submersible motor with plural cooling paths



March 22, 1966 J. 'r. CARLE 3,242,360

SUBMERSIBLE MOTOR WITH PLURAL COOLING PATHS Filed Feb. 9, 1961 5Sheets-Sheet 1 INVENTOR. JOSEPH T. CARLE BYWKW ATTORNEY.

J. T. CARLE March 22, 1966 SUBMERSIBLE MOTOR WITH PLURAL COOLING PATHS 5Sheets-Sheet 2 Filed Feb. 9, 1961 G 3 G F 82 INVENTOR.

\IJOSEPH T. CARLE BY M g M ATTORNEY.

J. T. CARLE March 22, 1966 'SUBMERSIBLE MOTOR WITH PLURAL COOLING PATHS5 Sheets-Sheet 5 Filed Feb. 9, 1961 ATTORNEY.

United States Patent 3,242,360 SUBMERSIBLE MOTOR WITH PLURAL COOLINGPATHS Joseph T. Carle, Tulsa, Okla, assignor to Borg-Warner Corporation,Chicago, 111., a corporation of Illinois Filed Feb. 9, 1961, Ser. No.88,223 1 Claim. (Cl. 31087) This invention relates to submersibleelectric motors adapted for insertion in deep wells for driving a pumptherein and has for its principal object the provision of such motorswith a new and improved means for circulating lubricating fluidtherethrough for improved cooling, lubrication and better filtering.

A general object of this invention is to provide for better cooling,lubrication and filtering in the motor elements of motors which arelimited in their diameter.

A still further object of this invention is to provide a submersiblemotor with means for directing cooling and lubricating fluid in primaryand secondary circulating zones so that a major portion of the fluid iscirculated through a heat exchanging zone for efiicient cooling .andfiltering while a portion of this main circulation is further directedthrough the secondary zone for circulation throughout the remainder ofthe motor.

A still further object of this invention is to provide a submersiblemotor with means for circulating cooling and lubricating fluid inprimary and secondary circulating zones and also to provide a means forcirculating such fluid to and from a bearing for heat exchanger zone ofa seal section used in connection with the motor; the latter zoneforming a portion of or an adjunct to the secondary zone.

A still further object of this invention is to provide the motor with ameans for directing cooling and lubricating fluid throughout the lengthof the rotor shaft and into the bearings thereof as well as along aportion of the outer periphery of the shaft intermediate the motor rotorproviding for greater circulation of cooling fluid without a loss inhorsepower and for a reduction in the number of hot spots in the motorand a reduction in the average operating temperature of the motor.

These and other objects of this invention will become apparent from thefollowing description when taken in connection with the accompanyingdrawings in which:

FIG. 1 is an elevational view of the submersible motor constructed inaccordance with the teachings of this invention;

FIG. 2 is a cross-sectional view taken along line 22 of FIG. 1 andlooking in the direction of the arrows;

FIG. 3a is a partial elevatioual cross-sectional view taken along line33 of FIG. 2 and illustrating to advantage the details of the upperportion of the submersible motor, FIG. 3a being only a portion of theentire motor by reason of the length thereof, for purposes ofillustration in these drawings;

FIG. 3b is a partial elevational cross-sectional view taken along line3-3 of FIG. 2 and showing a portion of the mid-section of the motornormally below that portion shown in FIG. 3a;

FIG. 30 is a partial elevational cross-sectional view taken along line33 of FIG. 2 and illustrating the details of the lower portion of themotor; FIG. 3c being normally disposed below trail portion shown in FIG.3b;

FIG. 4 is a cross-sectional partial schematic view taken along line 44of FIG, 3 showing the connection means for the outside source ofelectrical power to be supplied to the electric motor;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 3a,looking in the direction of the arrows, and illustrating to advantagethe flow path of the cooling and lubricating fluid in the motor shaft;

3,242,360 Patented Mar. 22, 1966 FIG. 6 is a cross-sectional view takenalong line 6-6 of FIG. 3a, looking in the direction of the arrows, andillustrating to advantage the centrifugal impeller mounted on the motorshaft for the circulation of the cooling and lubricating fluid; and

FIG. 7 is a cross-sectional view taken along line 77 of FIG. 3a, lookingin the direction of the arrows, and illustrating to advantage a bearingshoe through which cooling and lubricating fluid flows.

As can be seen in FIG. 1, a submersible motor for insertion in deepwells, constructed in accordance with the teachings of this invention,is indicated in its entirety as 10.

Submersible motor 10 has an outer multi-part housing or casing 11,suitably sealed, as by threading and welding as shown at 12, 13 and 14(FIGS. 31: and 30), so as to be fluid-tight to protect the inner motorelements from the fluid in the well. A stator 15, of the motor 10, isaflixed in any suitable manner to the inner side of the casing, as bysnap rings 16 and 17, and a motor rotor 18, is maintained on a motorshaft 19 in any suitable manner as by a key 20. The motor 10 is suppliedwith electrical power from a suit-able and conventional outside sourcethrough wiring connection shown schematically at 21 (FIG. 4).

Shaft 19 is maintained for vertical operation in upper bearings,indicated in their entirety as 22 (FIG. 3a), intermediate bearingsindicated in their entirety as 23 (one only showing 3b) and lowerbearings indicated in their entirety as 24 (FIG. 30), so that, upon theapplication of electric power through the stator coils 25, the rotor 18drives the shaft 19 to rotate a deep well pump (not shown). The upperend of the shaft 19 is externally splined, as illustrated at 26, to beconnected to a suitable seal assembly (not shown) usually andconventionally interposed between the deep well pump vand thesubmersible motor. Since the deep well pump and the seal may be ofconventional construction and do not form a part of the presentinvention, no further description thereof is deemed necessary herein.

As previously mentioned herein, an important feature of this inventionis the provision of means for circulating cooling and lubricating fluidso that this fluid maintains the motor cool as well as properlylubricated. This is accomplished preferably by the circulation of thefluid into two flow paths-a primary flow path and a secondary flowpath-and in such a manner that there is no reduction in the power outputof the motor. This feature will now be described.

At the lower end of the shaft 19, a centrifugal impeller 27 (FIGS. 30and 6) is suitably afiixed for rotation with the shaft 19, as by key 28.Outlet 29 of the impeller is in open communication with a passage 30formed in a bearing housing 31. Passage 30 is in turn in opencommunication with a cylindrical passage or space 32 formed in part bythe inner wall 33 of the casing 11 and in part by the outer wall 34 of aheat-resistant tube 35 of a smaller outer diameter than the innerdiameter of the easing 11. This heat-resistant tube 35 is 'aflixed tothe lower end of the bearing housing 31 and is formed of laminatedplastic material or the like, of any suitable type, to insulate chamber36 formed in part by such tube in cooperation with the bottom wall 37 ofthe casing 11. Thus, fluid pumped by the impeller 27 will travel fromthe outlet 29 into and through passage 30 and between, down the innerside wall 33 of the casing, and then into the inner chamber 36 through aplurality of ports 38 formed in the insulating tube 35. The casing 11serves as a 'heat exchanger to cool the coolant as it travels throughpassages 30' and 32 to the chamber.

Chamber 36 is normally filled with the cooling and lubricating fluid,such as oil, for lubricating the various parts of the motor, bearings,and the like, and as clearly seen, the shaft 19 is provided with aninternal concentric axial bore 40 throughout its length, the lower endof which is in open communication with the chamber 36.

In FIG. 3c it is to be noted that a chamber 41 is formed immediatelybelow and in part by the rotor and stator and in part by the upper endof the bearing housing 31. There is also provided a pair of radialpassages 42 which communicate with the shaft bore 40 and chamber 41.Thus, the cooling and lubricating fluid flowing up through the passage40 will flow or be thrown by the rotation of the shaft, out the radialpassages 42 into the chamber 41 where it communicates with a pair ofvertical inlet passages 43 and 44 in the bearing housing 31. Thesepassages in turn are in open communication with an inlet chamber 45immediate the inlet 46 to the impeller 27. Passages 43 and 44 aresuitably spaced from the shaft 19 to permit a conventional sleevebearing 47 and bushing 48 of previously identified lower bushing 24 tobe operatively interposed between the bearing housing 31 and the shaft,and to permit some circulation of the lubricating fluid to passtherebetween for proper lubrication and cooling.

Thus, it can be seen that, in this invention, there is a path of coolingand lubricating fluid from the impeller 27 past the 'heat exchangerformed by the casing 11, into the chamber 36 past a suitable filter 50interposed operatively between the shaft bore 40 and the chamber 36(filter 50 being shown in chamber), up the passage 40, out passages 42into chamber 41, and thence down the inlet passages 43 and 44 into theinlet chamber 45 to be again recirculated by the impeller past the heatexchanger. This forms a primary path of circulation of fluid andprovides a means of cooling and filtering a major portion of the oilduring operation of the motor.

As will be seen, a secondary path of circulation is provided comprisinga portion of fluid taken from the abovedescribed primary fluid so thatthe secondary circulation is always provided with a cool and filteredfluid without attempting to force the impeller to drive all of thecooling and lubricating fluid through the entire motor and back to thesump chamber. This maintains the coolant at an overall lower tempenaturethan could otherwise be accomplished.

Turning again to FIGS. 3a, 3b and 3c, it will be seen that the centralshaft bore 40, above the radial passages 42, continues on throughoutsubstantially the entire shaft up to and past the upper bearings 22.Intermediate the upper and lower hearings, pairs of radial passages 51are provided in the shaft Where necessary to provide the intermediatebearings 23 with proper cooling and lubricating fluid thrown out by therotating shaft from the passage 40. Intermediate bearings 23 comprise,in the embodiment shown, bushing 52 and a bearing ring 53, both of whichhave suitable means, such as openings 54, 55, to permit the flow oflubricant past the friction faces 56 and down between the stator or therotor. Inasmuch as these hearings are of conventional construction, nofurther description thereof is deemed necessary. As the number ofintermediate hearings will vary according to the length of the motor togive stability to the rotating parts, the number of such radial passages51 will vary accordingly, one pair of such passages 51 being shown inFIG. 3b for the purposes of illustration.

Another pair of radial passages 57 are provided intermediate theintermediate bearing passages 51 to properly lubricate between the longbushing guide 58 and the shaft '19 and between the pair of bushings 60,61, the former being provided between the upper part 62 of the casingand the shaft, as more clearly seen in FIG. 3a. Thus, there is a flow offluid firomthese passages down the inner side of the bush ing guide andbushing and thence into upper chamber 63 provided by the casing, theupper end of the stator and rotor, and the upper casing part 62. Thebushing guide and bushing are operatively held in their proper locationby any suitable means, such as by snap ring 64.

Still another, but somewhat larger pair of radial passages 65 areprovided in shaft 19 to communicate the shaft bore 40 with the upperbearings 22. Passages 65 communicate with a pair of radial passages 66provided in a thrust ring 67 which is turn is maintained for roe tationwith the shaft 19 by any suitable means; split ring 68, cap screws 70,lock ring 71 and key 72, being shown. Lubricating fluid is thrown outonto the bearing surfaces, onto thrust ring 67, and onto a non-rotatingbearing shoe or ring 73 for proper lubrication and cooling thereof.Casing part 62 is provided with a cavity 74 enlarged radially oppositethe bearing ring to receive the lubricant thrown out of the radialpassage 66 and to permit the flow of such fluid down and through aplurality of such passages or slots 75 in the bearing ring; such slotsbeing more clearly shown in FIG. 7. Slots 75 are in open communicationwith a pair of Iongitudinal passages or bores 76 and 77 formed in thecasing part 62. Bores 76 and 77 are, in turn, in open communication withchamber 63 so that there is circulation of lubricant from the passage 40in the shaft through the upper bearings 22. A suitable. restriction, asat 78, formed between the casing part 62 and the thrust bearing 67 isprovided so that the main flow of fluid from the passages 65 and 66 willbe downward towards the passages 75.

The shaft 19 is provided with a pair of longitudinal or coaxial grooves,diametrically opposed from one an-.

other, and, as more clearly shown in FIG. 5, at 90 from the key 20 asindicated at 80 and 81. These longitudinal grooves extend from that partof the shaft immediately above the rotor so that they open into thechamber 63 and continue below the rotor so that they open into thechamber 41, as more clearly shown in FIGS. 3a and 3c. Thus, fluid in thechamber 63 will flow down through these passages 80 and 81 between theshaft and the rotor to cool the same. Consequently, for properlubrication and cooling it is not necessary to rely upon the spacingnormally between the rotor and the stator, such spacing being indicatedat 82, to supply cooling fluid through the motor. As taught by thisinvention, the motor may be properly cooled by the circulation of morefluid than heretofore possible without attempting to provide morecirculation by enlarging the spacing or gap 82 to accomplish thispurpose thus reducing the efficiency of the motor.

As can also be seen at the top of FIG. 3a, the bore 40 of the shaft 19continues on through to be connected to a seal section (not shown)conventionally used in connection with the motor to isolate the motorfrom the Well fluid being pumped. As is conventional in such sealsections, a chamber is provided, as indicated schematically at 83. Suchchamber in the embodiment shown is also connected with the motor by apassage illustrated schematically as connected to the bore 40 so thatthe cooling and lubricating fluid circulating in the secondary zone ofthe motor may enter this chamber and be circulated by such flow offluid. Return flow may be provided by the passage, shown schematicallyat 85, so that fluid may pass through the restriction 78 to return totheprimary zone.

The chamber 83 has for its purpose a means for compensating for theexpansion and contraction of fluid in the motor due to the heating andcooling thereof during operation of the motor. This chamber receives theexpanded fluid during the running of the motor and permits thecontracting fluid to return to the motor and also prevents any wellfluid from entering the motor as it contracts.

As more particularly explained in the submersible seal disclosed andclaimed in the co-pending patent application of Joseph T. Carle entitledSubmersible Seal, Serial No. 88,096, now Patent No. 3,153,160, filedconcurrently herewith, the chamber 83 may have other functions. In thatapplication, such a chamber is a bearing and heat exchanger chamber sothat an important bearing in the seal chamber may be lubricated andcooled by the circulation of fluid in this chamber and also this chamberfunctions as a heat exchanger to cool such fluid as it returns to themotor. Thus, by the provision of a means of circulating this fluid inthe chamber during the operation of the pump, this fluid can bemaintained at a lower temperature than could otherwise be accomplishedto reduce the temperature of the bearing in the seal. It is to be noted,however, that while this motor is particularly adapted to be' used withthe seal section disclosed and claimed in said co-pending application,this motor may be utilized with any seal section having such a chamber,or with any other means for allowing for the expansion and contractionof fluid during operation of the motor; chamber 83 as shown hereinschematically, being illustrative of any expansion chamber which may beutilized.

From the above description it can be seen that there are two flow pathsin the submersible motor constructed in accordance with the teachings ofthis invention; a primary flow path to provide a large circulation ofcirculant past the heat exchanger for greater cooling and betterfiltering and, the secondary flow path so constructed and arranged toutilize a :portion of the flow from the primary flow path through theremainder of the motor and a portion of the expansion chamber and with afurther improvement of introducing cooling fluid down the outerperiphery of the shaft on the inner side of the rotor to cool the latterwithout interference and/or loss of efliciency of the motor.

While the various parts herein have been described as upper and lower orin a right or left position, such description refers only to therelative position of the parts as shown in the drawings and is notintended to be a limitation of the invention; it being understood thatthe appended claim should be construed as broadly as the prior art willpermit.

What is claimed is:

In a submersible motor, the combination of:

a motor casing;

a stator in said casing;

a motor shaft rotatably mounted in said casing;

a rotor mounted on and carried by said shaft;

an impeller having an inlet and an outlet adapted to circulate coolingand lubricating fluid within said motor casing;

spaced apart bearings rotatably supporting said shaft within said motorcasing;

an internal longitudinal bore formed within said shaft providing meansto circulate fluid therethrough;

radial passages formed in said shaft providing fluid communication fromsaid internal longitudinal bore to said bearings;

a first chamber formed in said casing above said rotor;

a heat exchange chamber formed in said casing below said rotor;

a groove formed in said shaft extending a distance from a location abovesaid rotor to a location below said rotor to provide fluid communicationbetween said shaft and said rotor; and

a gap formed between said rotor and said stator;

said internal bore providing fluid communication from said heat exchangechamber to said first chamber;

said groove and said gap providing parallel fluid communication pathsfrom said first chamber to said inlet;

said 'inlet being in fluid communication with said groove;

said heat exchange chamber being in fluid communication with saidoutlet.

References Cited by the Examiner UNITED STATES PATENTS 2,285,436 6/1942Hoover 3l087 2,315,917 4/1943 Arutunolf 31087 2,568,548 9/1951 Howard31087 2,736,825 2/ 1956 Hill 310-87 2,894,155 7/1959 Labastie 310-592,897,383 7/1959 Barrows et a1. 31068 2,938,131 5/1960 Maynard 310872,951,165 8/1960 Arutunoff 310-87 X 2,974,240 3/ 1961 Arutunoif 310-87FOREIGN PATENTS 1,087,959 3/ 1955 France.

ORIS L. RADER, Primary Examiner.

MILTON O. HIRSHFIELD, Examiner.

